US 5,307,983 AGranted

Method of making an article comprising solder bump bonding

AssigneeAT&T Bell Laboratories

InventorsThomas D. Dudderar, Chee C. Wong

Life of this patent

Estimating the term…

Loading patent…

Abstract

The present invention is embodied in a technique for precise and accurate height control in fabricating solder bumps or joints formed from a solder bump or bumps. A solder bump is formed by reflow of a conical solder body having base diameter D, height H and cone angle .theta., and has truncated sphere shape, with height h and truncation diameter d. We have found that D, H, and d can be selected such that .differential.h/.differential.H is small (typically .ltoreq.0.5), indicative of relative insensitivity of the bump height to variation in the height of the conical solder body. The inventive process is also applicable to a component (e.g., a laser) solder-bonded to a substrate, and can provide previously unattainable control of the spacing between component and substrate.

Claims8

Dependent claims

Method of making an article that comprises a first body attached to a second body (to be referred to as the "substrate") by means that comprise reflowable material (to be referred to as "solder"), the method comprising:

a) providing the substrate having a major surface that comprises at least one circular region of a first material that is wettable by the solder, said first material region being surrounded by a second material that is substantially not wettable by the solder, said first material region having diameter d;
b) forming on said first material region a substantially conical solder body associated with said solder body being a base of diameter D, a side wall, a conical height H and an angle .theta. (to be referred to as the "cone angle") between said base and said side wall;
c) causing said conical solder body to melt forming a molten material;
d) causing said molten material to re-solidify, such that a resolidified solder body (to be referred to as the first solder bump) results, said first solder bump having a truncated sphere shape, of height h, and truncation diameter d;
and
e) attaching the first body to the substrate by a process that comprises melting said solder bump;
Characterized In That
f) H, D, d and .theta. are selected such that a demagnification factor .differential.h/.differential.H, is less than or equal to 0.5.

5 more elements

Dependencies are inferred from the claim text.